The present invention relates generally to rotary wing aircraft and more particularly to a mounting assembly for the rotors of such aircraft. The invention is specifically directed toward the structure and configuration of a central headpiece for the rotor mounting assembly.
In a particular structural arrangement of a rotor mounting assembly known in the prior art, the rotor mounting supports or rotor support arms which have the rotor blade extending therefrom and which are formed at the rotor head, are structured as blade angle bearing sleeves. In the configuration referred to herein, which is known from German Pat. No. 2,150,741, the rotor blades are suspended at the rotor head by means of torsion-elastic tension laminae without flapping and laghinges. The rotor blades, which are equipped with metal fittings in the form of blade root sleeves, are each supported by two radial bearings which are constructed as roller bearings. The impact and bending moments which are created during operation of the device on each of the rotor blades are transmitted through radial bearings into the respective blade angle bearing sleeves or the central headpiece of the rotor.
Compared with constructions of the type which include flapping and laghinges, such a blade suspension system and support device provides significant weight reduction in the structure of the rotor head. However, a disadvantage arises in that comparatively high loads are created, particularly at the central headpiece which includes the blade support members. These loads generally result from shearing forces and bending moments. Therefore, high-strength metallic materials must be used for the purposes discussed. Such materials tend to be expensive and difficult to work with. Above all, they contribute significantly to an undesirably high structural weight of the overall rotor assembly.
The present invention is directed toward the objective of reducing structural weight and cost in a rotor assembly of the aforementioned type. Particularly, the invention is directed toward the overal configuration of the central headpiece of the rotor assembly which is designed to provide the aforementioned advantages without reducing dependability of operation and capacity for absorbing and withstanding rotor stresses.